I agree w/ Red58
the dome light wire may be connected to the lights post or you have a faulty switch. try tracing the dome wire and see what it's connected to. It may also just have come in contact w/ the lights post and is wired correctly. In that case simply move the terminals apart and insulate if necessary.
the neg. speaker post should go to ground so just connect a short wire to the new mounting bolt (or any frame bolt) of the speaker.

Jim & Caroline
The highway is for gamblers, better use your good sense."
Gooday-that's my 1¢ answer due to the lousy economy ~ cause I ain't got - no . mo . doe
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